1. Field of the Invention
The present invention is directed to a splitter that provides at least one “CATV & MoCA” output and at least one “MoCA only” output. More particularly, the present invention relates to low-cost splitter that can function as a building block to provide a customized installation configuration that supplies the needed number of “CATV & MoCA” outputs and the needed number of “MoCA only” outputs for a subscriber's premises.
2. Description of the Related Art
Cable television (“CATV”) networks are known types of communications networks that are used to transmit information between a service provider and a plurality of subscriber premises, typically over fiber optic and/or coaxial cables. The service provider may offer, among other things, cable television, broadband Internet and Voice-over-Internet Protocol (“VoIP”) digital telephone service to subscribers within a particular geographic area. The service provider transmits “forward path” or “downstream” signals from the headend facilities of the cable television network to the subscriber premises. “Reverse path” or “upstream” signals may also be transmitted from the individual subscriber premises back to the headend facilities. In the United States, the forward path signals are typically transmitted in the 54-1,002 MHz frequency band, and may include, for example, different tiers of cable television channels, movies on demand, digital telephone and/or Internet service, and other broadcast or point-to-point offerings. The reverse path signals are typically transmitted in the 5-42 MHz frequency band and may include, for example, signals associated with digital telephone and/or Internet service and ordering commands (i.e., for movies-on-demand and other services).
Each subscriber premises typically includes one or more power divider networks that are used to divide the downstream signals received from the service provider, so that the downstream signals may be fed to a plurality of service ports, such as wall outlets that are dispersed throughout the subscriber premises. These power divider networks also combine upstream signals that may be transmitted from one or more of the service ports into a composite upstream signal that is transmitted over the CATV network back to the headend facilities.
A recent trend is to use the coaxial cables that are installed throughout most homes, apartments and other subscriber premises as an “in-premises” network that may be used to transmit signals from a first end device that is connected to a first wall outlet in a subscriber premises to other end devices that are connected to other wall outlets in the subscriber premises. An industry alliance known as the Multi-media Over Coax Alliance (“MoCA”) has developed standards which specify frequency bands, interfaces and other parameters that will allow equipment from different standards-compliant vendors to be used to distribute multi-media content over such in-premises coaxial cable networks. These standards specify that such “MoCA” content is transmitted over the in-premises coaxial cable networks in the 850 MHz to 1675 MHz frequency band, although some service providers only distribute MoCA content within a narrower frequency band that is above the cable television band, such as, for example, the 1,125 MHz to 1,675 MHz frequency band. Thus, the MoCA content is transmitted over the in-premises network in a pre-selected MoCA frequency band. The power divider network in the in-premises network may be designed to support communications between its output ports in this pre-selected MoCA frequency band.
Examples of MoCA content that may be distributed over an in-premises coaxial cable network are digital television, video-on-demand programming and digitally-recorded television or music programming. In an exemplary application, such programming may be transmitted via the in-premises network of a home from a primary set-top box (which may be a full service set top box having a digital television receiver, DVR and/or video-on-demand capabilities, etc.) to less capable, less expensive, auxiliary set-top boxes that are installed on other televisions throughout the premises or directly to televisions, DVD players, etc. with MoCA ports. In this manner, the full capabilities of the primary set top box may be enjoyed at all of the televisions within the residence without having to provide a primary set top box for each television.
In many cases, significant attenuation may occur as signals are passed through the cable television network of a service provider, and hence the power level of the RF signal that is received at a subscriber premises may be on the order of 0-5 dBmV/channel. Such received signal levels may be insufficient to support the various services at an acceptable quality of service level. Accordingly, an RF signal amplifier may be provided at or near an entrance point of an individual subscriber's premises. The RF signal amplifier is used to amplify the downstream RF signals to a more useful level. The RF signal amplifier may also be configured to amplify the upstream RF signals that are transmitted from the subscriber premises to the headend facilities of the cable television network. Typically, the RF signal amplifiers are incorporated into the power divider network as the first unit, which takes the form of a powered bi-directional RF signal amplifier with an input port for receiving a coaxial cable from the service provider side and plural output ports which receive coaxial cables connected to the various service ports, such as the wall outlets that are dispersed throughout the subscriber's premises.
In accordance with the known power divider network unit, a RF signal amplifier receives a composite downstream RF signal of approximately 5 dBmV/channel in the range of approximately 54-1,002 MHz comprising information for telephone, cable television (CATV), Internet, VoIP, and/or data communications from a service provider. The RF signal amplifier may increase this downstream signal to a more useful level of approximately 20 dBmV/channel at each output port of the unit and pass the amplified downstream signal to one or more devices in communication with the RF signal amplifier through connections to the various coaxial wall outlets. Such devices may include, but need not be limited to: televisions, modems, telephones, computers, and/or other communications devices known in the art. In the event of power failure, an unamplified signals may still be passed (in both directions) through a passive communications path between the service provider and at least one communications device.
FIG. 1 illustrates a block diagram of a bi-directional RF signal amplifier 100 according to the background art. More information concerning the bi-directional RF signal amplifier 100 can be found in the Assignee's U.S. Pat. No. 9,699,516, granted on Jul. 4, 2017, the entire contents of which are herein incorporated by reference.
The RF signal amplifier 100 includes a plurality of RF output ports 181-188 that may be used to pass downstream and upstream signals between a service provider and multiple communications devices located in the subscriber premises when the RF signal amplifier is powered and operating normally. Moreover, RF signal amplifier 100 further includes a non-interruptible RF output port 189 that may be used to maintain bi-directional RF communications even during power outages.
As shown in FIG. 1, RF signal amplifier 100 includes a bi-directional RF input port 105 for receiving downstream RF signals from a service provider, or any other appropriate signal source. RF input port 105 can also pass upstream signals in the reverse direction from the RF signal amplifier 100 to the service provider. Due to the bi-directional nature of communications through RF signal amplifiers, it will be appreciated that an “input” port will act as an “output” port and an “output” port will act as an “input” port if the direction of signal flow is reversed. Consequently, it will be appreciated that the terms “input” and “output” are used herein solely for purposes of distinguishing various ports from one another, and are not used to require a direction of signal flow.
As noted above, RF signal amplifier 100 further includes a plurality of bi-directional output ports 181-189 that may be used to pass downstream RF signals from the RF signal amplifier 100 to one or more devices in communication with the output ports 181-189, and to receive upstream RF signals from those devices so that they may be passed through the RF signal amplifier 100 to the service provider. It will be appreciated that any appropriate device that may advantageously send and/or receive an RF signal may be placed in communication with one or more of the various output ports 181-189. For example, it is contemplated that telephone, CATV, Internet, VoIP, and/or data communication devices may be placed in such communication with a service provider where the RF signal amplifier 100 is installed in the residence of a subscriber. However, it will further be appreciated that any desired combination of these and/or other devices may be used where appropriate.
Signals received through RF input port 105 can be passed through RF signal amplifier 100 via an active communications path 114 that extends between RF input port 105 and RF output ports 181-188 and/or 189. Specifically, the downstream signals that are received at RF input port 105 from the service provider are passed to a passive directional coupler 110 that has a first output port that connects to the active communications path 114 and a second output port that connects to a passive communications path 118. The directional coupler 120 splits downstream RF signals onto the active communications path 114 and the passive communications path 118. It will be appreciated that the directional coupler 120 may either evenly or unevenly split the power of the downstream signals between the communications paths 114, 118, depending on the design of the overall circuit. The active communications path 114 amplifies at least one of downstream signals from the service provider to the subscriber premises or upstream signals from the subscriber premises to the service provider. The passive communications path 118 acts as a “non-interruptible” communications path that has no active components thereon, which allows downstream and/or upstream signals to traverse the passive communications path 118 even if a power supply to the RF signal amplifier 100 is interrupted. In some embodiments, the passive communications path 118 may provide a communications path for VoIP telephone service that will operate even during power outages at the subscriber premises (assuming that the modem and/or telephone, as necessary, are powered by a battery backup unit).
As is further shown in FIG. 1, downstream signals traversing the active communications path 114 pass from the first output of directional coupler 110 to an input port of a switching device such as, for example, an SPDT non-latching relay 120. A first output 122 of the relay 120 is connected to an input of a high/low diplexer 130. A second output 124 of the relay 120 is connected to a resistor 126, such as a 75 ohm resistor connected between the second output 124 and ground.
The diplexer 130 separates the high frequency downstream signal from any low frequency upstream signals incident in the reverse direction. In various embodiments, diplexer 130 can filter the signals in a manner such that signals with frequencies greater than approximately 45-50 MHz are passed as high frequency downstream signals, while signals with frequencies lower than such range are passed in the reverse direction as low frequency upstream signals received from ports 181-188. It will be appreciated, however, that other diplexer designs may be utilized.
The high frequency downstream signals filtered by diplexer 130 can be amplified by individual power amplifier 140, and passed through a second high/low diplexer 150 to a MoCA rejection filter 160. MoCA rejection filter 160 attenuates any frequencies in the MoCA frequency range. Typically, no signals in the downstream direction will contain MoCA frequencies and hence the downstream signal will be unaffected.
Next, the downstream signal passes to an input 169 of a power divider network 170. The power divider network 170 splits the downstream signal so that it may be distributed to each of ports 181-188. In the embodiment of FIG. 1, the power divider network 170 includes a power divider 171 in a first tier, feeding power dividers 172 and 173 in a second tier, feeding power dividers 174, 175, 176 and 177 in a third tier. The first, second and third tiers form a pyramid structure. While the power divider network 170 illustrated in FIG. 1 splits the downstream signals for distribution to eight different ports, it will be appreciated that the power divider network 170 may split the downstream signals for distribution to different numbers of ports (e.g., four, six, ten, etc.).
Turning now to the reverse (upstream) signal flow through the active communications path 114 of RF signal amplifier 100, upstream signals received by the RF signal amplifier 100 from devices in communication with ports 181-188 are passed to power divider network 170 where they are combined into a composite upstream signal. This composite upstream signal is fed out of input 169 through the MoCA rejection filter 160. The MoCA rejection filter 160 attenuates frequencies in the MoCA frequency range so as to prevent the MoCA signaling, which freely traverses between the ports 181-188, from entering the high/low diplexer 150. The high/low diplexer 150 separates the low frequency composite upstream signal from any high frequency downstream signals incident in the forward direction. As previously discussed in relation to diplexer 130, the diplexer 150 can filter the signals such that signals with frequencies greater than approximately 45-50 MHz are passed in the forward direction as high frequency downstream signals, while signals with frequencies lower than such range are passed in the reverse direction as low frequency upstream signals received from ports 181-188.
The composite low frequency upstream signal filtered by diplexer 150 can be passed directly to high/low diplexer 130 (or optionally the upstream signal filtered by the diplexer 150 can pass through an upstream power amplifier 142 prior to reaching the diplexer 130), where it is then passed through the first output port 122 of the non-latching SPDT relay 120 to the first output port of the directional coupler 110. The directional coupler 110 combines the upstream signal received at output port 122 with any upstream signal received from the passive communications path 118 and passes this combined signal to the RF input port 105 for output to a service provider or other entity in communication with RF input port 105.
The power amplifiers 140 and 142 that are included on the active communications path 114 are active devices that must be powered via a power source, such as a DC linear regulator 195 that outputs a power supply voltage VCC. During normal operation, the RF signal amplifier 100 can be powered from a power input port 190 and/or power that is reverse fed through one of the RF output ports (e.g., output port 188, which is labeled “VDC IN”). In a typical installation at a subscriber premises, it is contemplated that RF signal amplifier 100 may be powered by an AC/DC adapter receiving power provided by the residence (for example, 100-230 VAC, 50/60 Hz). As illustrated in FIG. 1, the power received from either power input 190 or power input 188 may be provided to the DC voltage regulator 195 which supplies an operating voltage VCC to the power amplifiers 140 and 142.
In the event that power to the DC voltage regulator 195 is interrupted, DC voltage regulator 195 will be unable to provide operating voltage VCC to power amplifiers 140 and 142. Consequently, during power outages, the downstream portion (and also the upstream portion, if the upstream power amplifier 142 is employed) of the active communications path 114 will be lost.
As noted above, RF signal amplifier 100 also has the passive communications path 118 that extends from the second output of the directional coupler 120 to the port 189. This passive communication path 118 bypasses the power amplifiers 140 and 142 and does not include any active components. Consequently, the passive communications path 118 will remain available to pass communications between port 105 and port 189, even when the power supply to RF signal amplifier 100 is interrupted. Accordingly, the passive communications path 118 is also referred to as a “non-interruptible” communications path. The passive communications path 118 may be used to maintain essential services to the subscriber premises such as, for example, 911 emergency lifeline services, even during power outages, so long as the subscriber has a battery backup for the necessary devices connected to port 189.
The passive communications path 118 is connected to the active communications path 114 at the input 169 of the power divider network 170. Within the passive communication path 118, upstream signals from the port 189 pass into an input 168 of a diplexer 162. Signals in the MoCA frequency range exit the diplexer 162 via output 164 and pass to the active communication path directly upstream of the power divider network 170. By this arrangement, MoCA signals from the port 189 may enter the input 169 of the power divider network 170. Hence, MoCA signals may be passed between all of the devices connected to ports 181-189.
The signals from the port 189 which pass into the input 168 of a diplexer 162, which are in the high/low frequency range for downstream and upstream communication with the service provider exit the diplexer 160 via output 166 and pass to the second output of the directional coupler 110, where the signals are combined with the signals on the active communication path 114 and are then passed to the port 105.
Additional background art can be found in U.S. Pat. Nos. 3,676,744; 6,969,278; 7,530,091; 8,695,055; 8,752,114; 8,810,334; 9,209,774; 9,356,796 and 9,743,038, and in U.S. Published Applications 2005/0044573; 2006/0205442 and 2013/0081096, which are herein incorporated by reference.